By Tribune Review.
While Mother Nature is not always predictable, fall foliage usually peaks with the brightest bursts of color in mid-October.
And this fall, forest ecologists in Penn State's College of Agricultural Sciences are predicting an awesome autumn foliage display, largely because of the rainy summer we've had. #PennStateUniversity #Agriculture #Autumn
"The cool, moist summer should usher in great fall colors," say Marc Abrams, professor of forest ecology and physiology, in a news release. "The robust physiology of the trees this year should predispose them to producing good color."
Kim Steiner, professor of forest biology and director of the Arboretum at Penn State, says, "One very positive sign this year is that I have noticed almost none of the early fall color that we often have after a dry August, especially on walnut and some red maples."
Cooler temperatures signal deciduous trees to stop producing chlorophyll, the green pigment responsible for photosynthesis, Abrams says. The chlorophyll breaks down and disappears, unmasking other leaf pigments, which create the yellows and oranges seen in the leaves of yellow poplar, hickory, sycamore, honey locust, birch, beech and certain maples.
After chlorophyll production stops, trees also produce another pigment in their leaves called anthocyanin, according to Abrams. The anthocyanins create the brilliant reds and purples seen in maple, sassafras, sumac, blackgum and scarlet oak.
"One thing that I have been impressed with in my 30 years of gauging foliage is the resiliency of the display," he says. "Year after year, despite the conditions, there are places where the trees show good color, but perhaps not great color every year. However, this year, the trees should be in great shape to show off their best colors."